HVAC systems are complex, and documenting them clearly can make or break your inspection report. Whether you're noting a dirty filter, condensate drainage issue, or recommending service, the right language protects you and informs your clients. This guide provides ready-to-use narratives for every common HVAC finding you'll encounter.

25+ Common Defects
30+ Sample Narratives
6 Key Systems
15-25 Year Lifespan

HVAC System Types at a Glance

Different HVAC systems have different inspection priorities. Know what to look for based on the system you're evaluating:

Split System

Critical Refrigerant Lines
Critical Condensate Drain
Important Filter Condition
Important Electrical Connections
Standard Cabinet Condition
Typical lifespan: 15-20 years

Gas Furnace

Critical Heat Exchanger
Critical Venting/Flue
Important Gas Supply
Important Burner Condition
Standard Blower Motor
Typical lifespan: 15-25 years

Heat Pump

Critical Reversing Valve
Critical Defrost Cycle
Important Auxiliary Heat
Important Outdoor Coil
Standard Thermostat Settings
Typical lifespan: 12-17 years

Pre-written HVAC narratives ready to use. HomeInspecto includes complete HVAC comment libraries for instant report generation. Schedule a demo →

Filter Condition: Most Common Finding

Filters are the first thing clients notice and the easiest defect to document. A dirty or missing filter can lead to system damage, poor air quality, and reduced efficiency. Here's how to write it up:

Satisfactory

Clean/New Filter

Filter appears recently replaced or in good condition with minimal debris accumulation.

Sample Narrative:

"The HVAC filter was inspected and found to be clean/recently replaced. Filter size: [20x25x1]. Recommend regular replacement per manufacturer guidelines (typically every 1-3 months)."

Maintenance

Dirty Filter

Filter shows significant debris accumulation restricting airflow.

Sample Narrative:

"The HVAC filter is dirty and restricting airflow. This condition reduces system efficiency, increases energy costs, and can lead to premature equipment failure. Recommend immediate replacement and regular maintenance schedule."

Repair Needed

Missing Filter

No filter installed—debris entering system and coating evaporator coil.

Sample Narrative:

"No HVAC filter is installed. Operating without a filter allows dust and debris to accumulate on the evaporator coil and blower components, reducing efficiency and potentially damaging the system. Recommend installing proper filter immediately."

Maintenance

Wrong Size Filter

Filter doesn't fit properly—gaps allowing unfiltered air bypass.

Sample Narrative:

"The HVAC filter is undersized for the filter housing, allowing unfiltered air to bypass the filter. This reduces filtration effectiveness and allows debris to enter the system. Recommend installing correctly sized filter."

Condensate Drainage Issues

Condensate problems are a leading cause of water damage and mold growth. Document these issues carefully with specific language:

Signs of Condensate Problems

Water Stains Staining on ceiling or walls near air handler
Standing Water Water in drain pan or around unit base
Algae/Mold Growth Biological growth in pan or drain line
Musty Odor Smell indicating biological growth
Float Switch Activated System shuts down due to pan overflow

Common Condensate Defects

  • Clogged drain line — Blocked with algae, debris, or sediment
  • Improper slope — Drain line not pitched for gravity flow
  • Missing trap — Required for negative pressure systems
  • Rusted drain pan — Corrosion causing leaks
  • Disconnected drain — Line separated from pan or termination
  • Improper termination — Draining into unacceptable location
  • No secondary drain/float switch — Missing backup protection

Condensate Defect Narratives

Safety Hazard

Active Water Leak

Water actively leaking from unit or condensate system causing immediate damage risk.

Sample Narrative:

"Active water leak observed at the HVAC air handler. Water is dripping from [location] causing damage to surrounding materials. Recommend immediate service by a qualified HVAC technician to prevent further water damage."

Repair Needed

Clogged Drain Line

Condensate drain line blocked—water backing up into drain pan.

Sample Narrative:

"The condensate drain line appears clogged. Standing water was observed in the drain pan, indicating improper drainage. This condition can lead to overflow, water damage, and mold growth. Recommend clearing the drain line and verifying proper flow."

Repair Needed

Rusted Drain Pan

Secondary drain pan shows corrosion that may lead to leaks.

Sample Narrative:

"The secondary condensate drain pan beneath the air handler shows significant rust and corrosion. This pan serves as backup protection against water damage. Recommend replacement before pan integrity is compromised."

Monitor

No Float Switch

No overflow protection device installed on drain pan.

Sample Narrative:

"No float switch or overflow protection device is installed on the condensate drain pan. A float switch shuts down the system if the pan fills, preventing water damage. Consider adding this safety device, especially for units located in attics or above living spaces."

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Airflow Issues & Temperature Differential

Proper airflow is essential for HVAC efficiency. Document airflow issues with specific measurements when possible:

Temperature Differential Guidelines

Cooling Mode 14-22°F Supply air should be 14-22°F cooler than return air
Heating Mode 15-30°F Supply air should be 15-30°F warmer than return air

Pro Tip: Always document the actual temperatures measured at supply and return registers, along with the calculated differential. Low differential may indicate low refrigerant, dirty coils, or restricted airflow.

Common Airflow Defects

Repair Needed

Low Temperature Differential

"Temperature differential measured at [X]°F (supply: [X]°F, return: [X]°F). Normal cooling differential is 14-22°F. Low differential may indicate low refrigerant charge, dirty evaporator coil, or restricted airflow. Recommend evaluation by a qualified HVAC technician."

Repair Needed

Weak/No Airflow at Register

"Little to no airflow detected at the supply register in [room]. This may indicate a blocked or disconnected duct, closed damper, or blower issue. Recommend further evaluation to identify the cause."

Monitor

Dirty Supply Registers

"Supply registers throughout the home show significant dust accumulation. While not affecting immediate function, this may indicate dirty ductwork or inadequate filtration. Recommend cleaning registers and evaluating duct condition."

Monitor

Return Air Restricted

"The return air grille is partially blocked by [furniture/debris]. Restricted return air reduces system efficiency and can cause premature equipment wear. Recommend maintaining clear space around return air grilles."

Age Assessment & Service Recommendations

Knowing when to recommend service versus replacement is critical. Use these guidelines and narratives:

Equipment Age Decoding

Most manufacturers encode the manufacture date in the serial number:

Carrier/Bryant Week & Year: 2519... = Week 25, 2019 First 4 digits = week + year
Trane/American Standard Year + Week: 194523... = 2019, Week 45 Digits in specific positions indicate date
Lennox First digits: 5819... = 2019 First 2 or 4 digits indicate year

Tip: Use the Building Intelligence Center website to decode serial numbers for any manufacturer.

Age-Related Narratives

Within Lifespan

"The HVAC system was manufactured in 2020 (approximately 5 years old). The system operated normally at the time of inspection. With proper maintenance, this equipment should provide several more years of service."

Approaching End

"The HVAC system was manufactured in 2012 (approximately 13 years old). While functional at the time of inspection, the unit is approaching the end of its typical service life (15-20 years). Budget for replacement in the coming years and maintain annual service."

Beyond Lifespan

"The HVAC system was manufactured in 2003 (approximately 22 years old), which exceeds the typical 15-20 year service life. While operational at the time of inspection, replacement should be anticipated. The system also uses R-22 refrigerant, which is no longer manufactured."


HVAC Service Recommendation Language

Use these professionallyworded service recommendations based on your findings:

Routine Maintenance

"Recommend annual HVAC maintenance service to ensure continued efficient operation, identify potential issues early, and extend equipment life."

When: No defects found, general recommendation

Service Before Closing

"Recommend service by a qualified HVAC technician prior to closing to evaluate [specific concern] and ensure proper operation."

When: Minor defects or concerns noted

Immediate Service Required

"The HVAC system requires immediate service by a qualified technician. Do not operate until [issue] has been evaluated and corrected."

When: Safety concerns or major defects

Replacement Recommended

"Given the age and condition of the HVAC system, replacement should be anticipated. Recommend obtaining estimates from qualified HVAC contractors."

When: Equipment beyond useful life

Complete HVAC narrative library included. HomeInspecto auto-generates age estimates and recommends appropriate service language based on system condition. Start your free trial →

Photo Documentation Checklist

The right photos protect you and help clients understand issues. Capture these for every HVAC inspection:

1

Data Plate

Shows model, serial number, capacity, and efficiency rating. Essential for age verification.

2

Filter Condition

Document filter condition and size. Show dirty filters clearly.

3

Condensate Pan & Drain

Show pan condition, drain connection, and any water accumulation.

4

Outdoor Unit

Overall condition, clearances, refrigerant lines, and electrical disconnect.

5

Thermostat

Settings, temperature display, and any error codes.

6

Temperature Readings

Your thermometer at supply and return showing measured temps.

7

Ductwork (Visible)

Condition, connections, insulation, and any damage visible.

8

Any Defects

Close-ups of rust, damage, leaks, or other issues found.

Frequently Asked Questions

Should I test both heating and cooling modes?

Test all modes available for the conditions. Avoid testing cooling when outdoor temps are below 60°F (can damage the compressor) and heating when indoor temps are already high. Document which modes were tested and why any modes were not tested. Example: "Cooling mode not tested due to outdoor temperature below 60°F—could damage compressor."

How do I report a system that won't start?

Document what you observed and attempted: "The HVAC system did not respond when the thermostat was set to [heat/cool]. Verified thermostat was set correctly and temperature differential was adequate to trigger operation. System may have a failed component, tripped breaker, or other issue. Recommend evaluation by a qualified HVAC technician."

What if the system uses R-22 refrigerant?

R-22 (Freon) was phased out January 1, 2020. Note this in your report: "The air conditioning system uses R-22 refrigerant, which is no longer manufactured. If a refrigerant leak develops or service is needed, repairs may be cost-prohibitive due to limited R-22 availability. Consider this when planning for future replacement."

Should I note the SEER rating?

Yes, if visible on the data plate. Higher SEER = more efficient. Current minimum is 14-15 SEER depending on region. Example: "The air conditioning system is rated at 10 SEER. Current minimum efficiency standards require 14-15 SEER for new installations. Upgrading to a higher-efficiency system would reduce cooling costs."

How should I document unusual noises?

Be specific about the noise type and location: "A [grinding/squealing/rattling/banging] noise was heard coming from the [indoor unit/outdoor unit/ductwork] during operation. This may indicate [worn bearings/loose components/duct expansion/etc.]. Recommend evaluation by a qualified HVAC technician to identify the source."